Small Cell Networks

Deployment, Management, and Optimization

Holger Claussen, David Lopez-Perez, Lester Ho, Rouzbeh Razavi, Stepan Kucera

• Publisher: Wiley-IEEE Press
• Year: 2017
• ISBN:
  9781119307587
• Edition: 1
• Topic: Technology & Engineering
• Subtopic: Electrical Engineering & Telecommunications
• Index: Technology & Engineering

The first and only up-to-date guide offering complete coverage of HetNets—written by top researchers and engineers in the field

Small Cell Networks: Deployment, Management, and Optimization addresses key problems of the cellular network evolution towards HetNets. It focuses on the latest developments in heterogeneous and small cell networks, as well as their deployment, operation, and maintenance. It also covers the full spectrum of the topic, from academic, research, and business to the practice of HetNets in a coherent manner. Additionally, it provides complete and practical guidelines to vendors and operators interested in deploying small cells.

The first comprehensive book written by well-known researchers and engineers from Nokia Bell Labs, Small Cell Networks begins with an introduction to the subject—offering chapters on capacity scaling and key requirements of future networks. It then moves on to sections on coverage and capacity optimization, and interference management. From there, the book covers mobility management, energy efficiency, and small cell deployment, ending with a section devoted to future trends and applications. The book also contains:

• The latest review of research outcomes on HetNets based on both theoretical analyses and network simulations
• Over 200 sources from 3GPP, the Small Cell Forum, journals and conference proceedings, and all prominent topics in HetNet
• An overview of indoor coverage techniques such as metrocells, picocells and femtocells, and their deployment and optimization
• Real case studies as well as innovative research results based on both simulation and measurements
• Detailed information on simulating heterogeneous networks as used in the examples throughout the book

Given the importance of HetNets for future wireless communications, Small Cell Networks: Deployment, Management, and Optimization is sure to help decision makers as they consider the migration of services to HetNets. It will also appeal to anyone involved in information and communication technology.

Part I
Introduction

1
Small Cells—The Future of Cellular Networks

1.1 Introduction

“Any sufficiently advanced technology is indistinguishable from magic.”

—Arthur C. Clarke, Profiles of the Future

One of the most widely used devices that appears “magical” today is the smartphone, which allows the user to connect instantaneously with people anywhere on the planet, can provide professional answers to any question, has access to a map of the entire world, and can guide the user to any desired destination.

However, the “magic” does not occur in the smartphone but in the network, which enables its functionality, provides ultra-broadband wireless access, and processes information to deliver voice and data services, invisible to the user.

Popular user demand has thus fueled a remarkable growth of cellular network infrastructure and mobile devices. In 2014, the number of connected mobile devices for the first time exceeded the number of people on Earth, increasing rapidly from zero to 7.6 billion connected devices and 3.7 billion unique subscribers in only three decades [1, 2]. This has fundamentally transformed the way we communicate and access information.

Today, we are on the brink of another significant change. While up to now the network mainly served humans, in the future, this capability will increasingly be used by machines as well. The emergence of machine-originated data traffic not only drives further the demand for network capacity but also imposes additional requirements on network performance, mainly in the area of end-to-end latency, which currently is the limiting factor for many new applications.

Nowadays, most of the data services reside in the Internet, far away from the user where the speed of light becomes one of the main factors limiting latency. To address this problem, processing will have to move closer to the user into a cloud computing infrastructure as part of the network. In addition, adaptive network management and well-designed congestion control can help to control latencies and enable new real-time applications such as augmented reality or efficient machine communication.

With these changes, the future network is evolving to become our main interface with the virtual world, and increasingly also with the physical world, to simplify and automate much of life. This will allow us to effectively “create time” by improving the efficiency in everything we do [3].

Making this vision of the future network a reality will require both:

1. Ultra broadband wireless access, providing orders of magnitude improved performance and quality-of-service control, as well as
2. A flexible and programmable cloud computing infrastructure located close to the edge of the wireless network.

Throughout this book, we argue that small cells are the answer to the technological challenges of creating a wireless access network that connects the mobile devices, machines and objects to a processing cloud engine.

As an introduction to our technological philosophy and the content of the book, the remainder of this chapter first summarizes the industry challenge, followed by an overview of the small cell technology and its history. Then, individual parts and chapters of the book are introduced as well as their relationship to various aspects of deploying and operating small cell networks.

1.2 The Industry Challenge

The proliferation of highly capable mobile devices as well as the user expectation to be fully connected and have access to all services anywhere and anytime has resulted in an exponential increase in cellular capacity demand over the past few years. With the addition of wirelessly connected machines, which can send, receive, and process massive amounts of data, this trend will continue and is driving an explosion of cellular capacity demand. The expectations are that machines will significantly outnumber human users in the future.

Figure 1.1 shows the predicted increase in data traffic until 2025, taken from an analysis done by Bell Labs Consulting in 2014 based on LTE traffic models and drawing from multiple data sources, including Alcatel-Lucent field data and [1, 4, 5, 6]. It is shown that the global bearer traffic is expected to grow by a factor between 61× and 115× over the next decade to 22.5 Exabytes per year [7].

Figure 1.1 Growth in capacity demand [7].

Moreover, the control plane demand is predicted to increase proportionally to support an increasing number of short traffic messages generated by machines [7].

However, although the demand for capacity is increasing, users are not willing to pay substantially more for higher data rates, and the average revenues per unique subscriber in recent years have been stagnating [8]. This means we have to provide exponentially more capacity for the same costs as today, adding a significant commercial challenge to the already difficult physical challenge of scaling capacity by orders of magnitude.

A further difficulty is the energy consumption of networks. A report from Ofcom suggests that information communication technology (ICT) accounts for 2% of global CO2 emission with 0.7% contribution from mobile and fixed communication devices [9]. For example, British Telecom consumes 0.7% of all electricity usage in the United Kingdom [10]. The energy consumption already accounts for 7–15% of operational expenditure (OPEX), reaching up to 50% in developing countries. As a result, we cannot scale capacity using traditional macrocellular network technology, since this would quickly become unsustainable both from a commercial and environmental point of view.

In summary, we can state the industry challenge as enabling orders of magnitude increase in wireless capacity without increasing costs.

1.3 Are Small Cells the Answer?

1.3.1 Dimensions for Capacity Scaling and Historic Capacity Gains

When aiming at orders of magnitude improvements of network capacity, it is important to understand the different dimensions of how capacity can be improved. In a simplified form, the Shannon–Hartley theorem

(1.1)

provides an insight into what are the variables that influence the amount of information (capacity C) one can transmit over a communication channel of a specified bandwidth B with a signal received with power S in the presence of white Gaussian noise with power N [11].

Capacity C can be scaled by increasing the bandwidth B per user, and by increasing the signal-to-noise ratio S/N, or in a multi-user network the signal-to-interference-plus-noise ratio (SINR). Addressing the bandwidth is a more promising approach since this results in a linear scaling compared to the logarithmic scaling when increasing spectral efficiency by improving the SINR. In a network with multiple users, the bandwidth per user can be scaled by either increasing the frequency resources, or by network densification based on the reduction of cell size. This measure results in improved spatial reuse of frequency resources and less sharing of the available bandwidth between users.

An overview of how each of the three degrees of freedom governing wireless channel capacit...

Table of contents

• Cover
• IEEE Press
• Title page
• Copyright
• ABOUT THE AUTHORS
• FOREWORD
• ACRONYMS
• PART I INTRODUCTION
• PART II COVERAGE AND CAPACITY OPTIMIZATION
• PART III INTERFERENCE MANAGEMENT
• PART IV MOBILITY MANAGEMENT AND ENERGY EFFICIENCY
• PART V SMALL CELL DEPLOYMENT
• PART VI FUTURE TRENDS AND APPLICATIONS
• A SIMULATING HETNETS
• INDEX
• IEEE Press Series on: Networks and Services Management
• EULA